Flutter Firebase Messaging 无法创建服务 io.flutter.plugins.firebasemessaging.FlutterFirebaseMessagingService

Question

我正在尝试在 Flutter 应用程序中使用 Firebase 消息传递。我遵循包装中的所有说明。

在我的 pubspec.yaml 我有这些包：

dependencies:
  flutter:
    sdk: flutter
  ...
  firebase_messaging: ^5.1.5
  ...

我的 main.app 就是这样：

void main() {
  runApp(MyApp());
}

MyApp 是一个 StatefullWidget，在 _MyAppState 我有：

    FirebaseMessaging firebaseMessaging = FirebaseMessaging();
   @override
  void initState() {
    super.initState();
    NotificationHandler().initializeFcmNotification();
  }

所有代码都在notification_handler.dart 中（感谢@HarishPenta）：

...
import 'package:firebase_messaging/firebase_messaging.dart';
...

class NotificationHandler {
  FlutterLocalNotificationsPlugin flutterLocalNotificationsPlugin;
  FirebaseMessaging _fcm = FirebaseMessaging();
  StreamSubscription iosSubscription;
  static final NotificationHandler _singleton =
  new NotificationHandler._internal();

  factory NotificationHandler() {
    return _singleton;
  }
  NotificationHandler._internal();

  Future<dynamic> myBackgroundMessageHandler(
      Map<String, dynamic> message) async {
    print("onLaunch: $message");
    // Or do other work.
  }

  initializeFcmNotification() async {
    flutterLocalNotificationsPlugin = new FlutterLocalNotificationsPlugin();

    var initializationSettingsAndroid =
    new AndroidInitializationSettings('ic_launcher');
    var initializationSettingsIOS = new IOSInitializationSettings(
        onDidReceiveLocalNotification: onDidReceiveLocalNotification);
    var initializationSettings = new InitializationSettings(
        initializationSettingsAndroid, initializationSettingsIOS);
    flutterLocalNotificationsPlugin.initialize(initializationSettings,
        onSelectNotification: onSelectNotification);

    if (Platform.isIOS) {
      iosSubscription = _fcm.onIosSettingsRegistered.listen((data) {
        // save the token  OR subscribe to a topic here
      });

      _fcm.requestNotificationPermissions(IosNotificationSettings());
    } else {
      _saveDeviceToken();
    }

    _fcm.configure(
      onMessage: (Map<String, dynamic> message) async {
        print("onMessage: $message");
      },
      //onBackgroundMessage: myBackgroundMessageHandler,
      onLaunch: (Map<String, dynamic> message) async {
        print("onLaunch: $message");
      },
      onResume: (Map<String, dynamic> message) async {
        print("onResume: $message");
      },
    );
  }

...}

在我的 AndroidManifest.xml 我有：

<activity
            android:name=".MainActivity"
...
<intent-filter>
                <action android:name="FLUTTER_NOTIFICATION_CLICK" />
                <category android:name="android.intent.category.DEFAULT" />
            </intent-filter>

最后，在 app/src/main/java//Application.java 我有：

package <my ID app>;  --> the same ID in google-services.json

import io.flutter.app.FlutterApplication;
import io.flutter.plugin.common.PluginRegistry;
import io.flutter.plugins.GeneratedPluginRegistrant;

import io.flutter.plugin.common.PluginRegistry.PluginRegistrantCallback;
import io.flutter.plugins.firebasemessaging.FlutterFirebaseMessagingService;


public class Application extends FlutterApplication implements PluginRegistry.PluginRegistrantCallback {
    @Override
    public void onCreate() {
        super.onCreate();
        FlutterFirebaseMessagingService.setPluginRegistrant(this);
    }

    @Override
    public void registerWith(PluginRegistry registry) {
        GeneratedPluginRegistrant.registerWith(registry);
    }
}

好吧，应用程序启动正常，并且在前台，当我发送通知时，应用程序停止，我可以看到以下错误消息：

D/AndroidRuntime(26933): Shutting down VM
E/AndroidRuntime(26933): FATAL EXCEPTION: main
E/AndroidRuntime(26933): Process: br.com.htsnet.emergencia, PID: 26933
E/AndroidRuntime(26933): java.lang.RuntimeException: Unable to create service io.flutter.plugins.firebasemessaging.FlutterFirebaseMessagingService: java.lang.RuntimeException: PluginRegistrantCallback is not set.
E/AndroidRuntime(26933):    at android.app.ActivityThread.handleCreateService(ActivityThread.java:3167)
E/AndroidRuntime(26933):    at android.app.ActivityThread.access$1900(ActivityThread.java:177)
E/AndroidRuntime(26933):    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1532)
E/AndroidRuntime(26933):    at android.os.Handler.dispatchMessage(Handler.java:102)
E/AndroidRuntime(26933):    at android.os.Looper.loop(Looper.java:145)
E/AndroidRuntime(26933):    at android.app.ActivityThread.main(ActivityThread.java:5951)
E/AndroidRuntime(26933):    at java.lang.reflect.Method.invoke(Native Method)
E/AndroidRuntime(26933):    at java.lang.reflect.Method.invoke(Method.java:372)
E/AndroidRuntime(26933):    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1400)
E/AndroidRuntime(26933):    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1195)
E/AndroidRuntime(26933): Caused by: java.lang.RuntimeException: PluginRegistrantCallback is not set.
E/AndroidRuntime(26933):    at io.flutter.plugins.firebasemessaging.FlutterFirebaseMessagingService.startBackgroundIsolate(FlutterFirebaseMessagingService.java:157)
E/AndroidRuntime(26933):    at io.flutter.plugins.firebasemessaging.FlutterFirebaseMessagingService.onCreate(FlutterFirebaseMessagingService.java:77)
E/AndroidRuntime(26933):    at android.app.ActivityThread.handleCreateService(ActivityThread.java:3157)
E/AndroidRuntime(26933):    ... 9 more

我正在使用 Android Studio 3.5，Firebase 函数在 paypload 中发送带有数据的通知（click_action：'FLUTTER_NOTIFICATION_CLICK'）。

Answer 1

在您的 android/app/main/java/com/ 中添加以下提到的文件

应用程序.java

package com.example.<application Name>;
import io.flutter.app.FlutterApplication;
import io.flutter.plugin.common.PluginRegistry;
import io.flutter.plugin.common.PluginRegistry.PluginRegistrantCallback;
import io.flutter.plugins.firebasemessaging.FlutterFirebaseMessagingService;

public class Application extends FlutterApplication implements PluginRegistrantCallback {
  @Override
  public void onCreate() {
    super.onCreate();
    FlutterFirebaseMessagingService.setPluginRegistrant(this);
  }

  @Override
  public void registerWith(PluginRegistry registry) {
    FirebaseCloudMessagingPluginRegistrant.registerWith(registry);
  }
}

FirebaseCloudMessagingPluginRegistrant

package com.example.<application Name>;
import io.flutter.plugin.common.PluginRegistry;
import io.flutter.plugins.firebasemessaging.FirebaseMessagingPlugin;

public final class FirebaseCloudMessagingPluginRegistrant{
  public static void registerWith(PluginRegistry registry) {
    if (alreadyRegisteredWith(registry)) {
      return;
    }
    FirebaseMessagingPlugin.registerWith(registry.registrarFor("io.flutter.plugins.firebasemessaging.FirebaseMessagingPlugin"));
  }

  private static boolean alreadyRegisteredWith(PluginRegistry registry) {
    final String key = FirebaseCloudMessagingPluginRegistrant.class.getCanonicalName();
    if (registry.hasPlugin(key)) {
      return true;
    }
    registry.registrarFor(key);
    return false;
  }
}

主要活动

package com.example.<application Name>;
import android.os.Bundle;
import  `io.flutter.app.FlutterActivity`;
import `io.flutter.plugins.GeneratedPluginRegistrant`;

public class MainActivity extends FlutterActivity {
  @Override
  protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    GeneratedPluginRegistrant.registerWith(this);
  }
}

Answer 2

我面临同样的问题：刚刚从 android 项目中删除了“Application.class”。代码工作正常。